Effects of automatic prestimulation in the milking of Manchega sheep.

• Mechanical stimulation during sheep milking entails a worsening of the milk flow rate values. • Mechanical stimulation during sheep milking has not shown benefits in milking fractioning. • In sheep, when pulsators are set up at 300 cycles /min, the opening of milking liners opening is incomplete. Milking machine manufacturers have developed new lines of pulsators with the option of practicing automatic stimulation of the teats. The aim of this study was to test the effect of previous automatic stimulation on Manchega sheep milking fractioning, milking duration and milk flows, teat-end status and vacuum levels at the short milk and pulsation tubes. Two similar groups of sheep were employed in one experiment in Latin square design. One group was milked with a mechanical prestimulation of 300 cycles/min during a 20 s period and the other group was milked without prestimulation. Results showed that prestimulation presented lower average milk flow (kg/min) values (0.73 ± 0.03 vs 0.66 ± 0.03; p < 0.01) during the stimulation and in the main milking phase (0.74 ± 0.03 vs 0.65 ± 0.03; p < 0.01), with no consequences in the variables related to milking fractioning or teat-end status. Additional long-term studies are needed to evaluate the effect of previous automatic stimulation on milk yield during lactation, chemical composition of the milk and health status of the udder. [ABSTRACT FROM AUTHOR]